Dutasteride, which is chemically known as 17β-N-[2,5-bis (Trifluoromethyl) phenyl]carbamoyl-4-aza-5-α-androst-1-en-3-one (formula (I)), is useful in the treatment of androgen responsive and mediated diseases.
U.S. Pat. No. 5,565,467, incorporated herein by reference, describes and claims dutasteride and related compounds, the pharmaceutical formulations containing them, and their use in the treatment of androgen and mediated diseases. The '467 patent discloses a process for preparation of dutasteride, which includes dehydrogenation of 17β-N-(2,5-bis (trifluoromethyl)phenyl)carbamoyl-4-aza-5α-androstane-3-one in the presence of catalysts 2,3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) and bis (trimethylsilyl)trifluoroacetamide in dioxane as solvent and the resultant solid is crystallized from a mixture of ethyl acetate—heptane at a ratio of 1:1 v/v. International Application No. WO 9507927 discloses a process for isolation of pure dutasteride by crystallization of crude dutasteride in methanol and acetonitrile. Nevertheless, new forms of dutasteride and new methods of making dutasteride are desirable.